1. Field of the Invention
The present invention relates to an ancillary conveyance to adjust the transport speed of a workpiece while supported on a conveyor driven at a constant speed for the supply and/or discharge of workpieces to a decorating machine conveyor of an intermittent motion type-decorating machine, preferably incorporating an improved workpiece registration station.
2. Description of the Prior Art
U.S. Pat. Nos. 2,231,535; 2,261,255; 2,721,516; 3,146,705; 3,388,574; and 5,524,535 disclose intermittent motion type decorating machines using an indexing drive system to impart intermittent traveling motion to an endless chain conveyor provided with workpiece carriers for supporting workpieces such as bottles made of glass or plastic. U.S. Pat. No. 3,388,574 discloses horizontally orientated bottle carriers arranged in a side-by-side relation on a conveyor chain and used for supporting each bottle in a horizontal orientation while intermittently moved along a path of travel through a decorating machine. Each bottle is supported at its opposite ends by clamping chucks. One chuck, rotated by a machine drive, is temporarily connected with a crank arm on a journal extending from a bearing support. The other clamping chuck is resiliently moveable by a spring to release and resiliently the bottle for rotation about a horizontal axis extending along the extended length of the bottle. The clamping chucks are supported on a base, which is secured to chain-links forming the endless conveyor chain extending along the path of travel of bottles through the decorating machine. The clamping force acting on the bottle by the clamping chucks is the only force retaining the bottle on the conveyor. The effect of inertia acting on the bottle in response to the intermittent motion at a given through put speed must be offset by the clamping force. However, the magnitude of the clamping force establishes a break away force for relative rotation between the bottle and the clamping chucks for registration of the bottle relative to the decoration cycle by the machine.
In these known forms of intermittent motion decorating machines, a bottle is moved by the endless chain conveyor driven by an indexing drive through a predetermined distance, stopped, moved again through a predetermined distance, stopped and again moved until each bottle is advanced by the sequence of motions completely through all of the decorating stations of the decorating machine. A decorating station is provided at one or more places along the conveyor where the bottle comes to a stop. Additionally, a registration drive is arranged along the conveyor between the bottle loading station and the first decorating station. The registration drive rotates the bottle and uses an indexing finger to engage in a recess in the wall of the bottle. This action causes a slip clutch action by the stoppage to the rotation of the bottle while the driven clamping chuck continues to rotate to a completion of the registration cycle. The stoppage to the rotation of the bottle establishes a predetermined orientation of the bottle surface relative to a decorating station and serves for orientating the bottle particularly the usual seam line in the bottle surface formed by the parting line of the parsons mold part relative to the printing screen at each decorating station. One half of the decorating cycle is used for decorating the bottles and the remaining half of the cycle is used for the indexing movement of the bottle through the decorating machine. At each decorating station while the bottle is stopped from traveling motion, a decorating screen is displaced into line contact by an associated squeegee with the surface of the bottle while the bottle is rotated about the longitudinal axis thereof. During the first part of the decorating cycle, the screen is moved synchronous with the peripheral speed of the rotating bottle to avoid smearing during decoration at the line of contact established between a squeegee and the bottle. The squeegee remains stationary during the decorating process. When the screen moves to the end of its travel, the bottle has rotated 360° whereupon the screen drive mechanism maintains the screen stationary for the remaining part of the decorating cycle while the bottle is removed from the decorating station and an undecorated bottle is moved to the decorating station.
Thermosetting ink was usually the printing medium in such intermittent motion decorating machines, particularly when multiple color decoration was applied to the bottles. Ink of only one color is applied at each decorating station and to decorate with multiple colors requires a corresponding number of decoration stations. When the different colors interleave in a given area of the bottle and therefore, because the same area is contacted with a screen for applying each color, it is necessary that the applied ink/color is solid and will not smear before each additional ink/color is applied. Although the thermosetting ink is solidified after each printing operation, it is necessary to cure the ink usually by feeding the bottles through a furnace after discharging from the decorating machine. In U.S. Pat. No. 6,079,326, curing of an ink decoration is completed after applied at one decorating station before an additional decoration is applied. The dwell period to the intermittent advancing motion by the conveyor chain is used to both apply ink decoration and to cure the applied decoration all at spaced apart sites along the course of travel by the bottles in the decorating machine. All the decoration on a bottle when delivered from the decoration machine is cured so that the bottles can be loaded directly into a shipping container without the need to cure the decoration in a furnace.
As disclosed in U.S. Pat. No. 5,524,535 the machine cycle in an intermittent motion decorating machine is altered to attain an increase to the workpiece decoration rate. The altered machine cycle provides that the portion of the cycle for conveyor indexing have a reduced duration in order to provide an increased part of the machine cycle for decorating. The conventional chain conveyor required an indexer drive to transmit the torque required to rapidly accelerate and decelerate a chain conveyor laden with carriers and including the compliment of bottles or workpieces processed in a decorating machine. A deviation to the use of a chain conveyor for workpieces in an intermittent decorating machine is disclosed in U.S. Pat. No. 6,073,553 and notably includes the use of elongated barrel cams and transfer disks arranged to provide a continuous traveling motion to the horizontal workpiece carriers. The traveling motion of the horizontal carriers is interrupted only at each decorating station and, when provided, at each curing station. The continuous traveling motion greatly increased the through put rate for workpieces in the decorating machine.
The present invention provides an increase to the rate at which the workpieces are delivered and, if desired, supplied to an intermittent motion decorating machine. The handling of workpieces particularly bottles demand the use of constraints as they are manipulated during the feeding operation from a source of supply and discharged from the decorating conveyor. The glass forming operations employed to produce the bottle also impose dimensional variations to the bottles that must be accommodated particularly during high speed handling by the bottle at the entry and delivery equipment as well as during passage through the actual bottle decorating machine.
The present invention further seeks to provide a workpiece steadying apparatus to alter the transfer speed of workpieces individually and consecutively from a delivery rate by a decorating transfer conveyor as received from the transfer operation carried out simultaneously with a reorientation of the workpiece. The change to the workpiece orientation, such when the workpiece comprises a bottle, has been carried out in the past as shown in U.S. Pat. No. 3,648,821 in which a conveyor supplies the bottles in a vertical orientation to a point where they are orientated horizontally and transferred to a conveyor of a decorating machine. The bottles are decorated while horizontally orientated and then delivered from the decorating machine by a transfer device to a discharge conveyor. The transfer device orientates the bottles from the horizontal to the vertical for conveyance by the discharge conveyor. When the rate at which bottles are fed through the decorating machine increases, there is also the need to captivatingly hold the bottle while supplied by the the feed conveyor to the conveyor of the decorating machine and while transported by the conveyor of the decorating machine to the delivery conveyor. Also, the motions necessary to grip and release the workpiece during these transferring operations must be executed with great precision to insure successful handling of the workpiece that necessarily requires that the workpiece be taken from the freestanding vertically, stable attitude, re-orientated to the horizontal and placed in a wholly confined driven conveyor and taken from the driven conveyor, re-orientated from the horizontal to again regain a free-standing vertically, stable attitude.
It is an object of the present invention to provide a method and apparatus for adjusting the conveyance speed and at the same time stabilizing a workpiece particularly a bottle during delivery from and, if desired, delivery to a decorating machine.
It is a further object of the present invention to provide, in a decorating machine, horizontal workpiece carriers continuously advanced except at each of a plurality of spaced decorating stations and a registration station wherein the latter establishes the registration of the workpiece orientation at a reduced clamping pressure on the carriers which is restored to a predetermined clamping pressure for receiving decoration at each of the subsequent decorating stations.